湍流边界层雷诺应力和壁脉动压强相位滞后分析

Phase delay of the Reynolds stress and wall pressure fluctuation in wall shear flows

在风洞平板湍流边界层外层引入圆柱尾涡的周期性扰动,在尾流干扰下的湍流边界层内进行测量,对相位滞后关系进行了实验研究,给出了湍流边界层内的雷诺应力和壁面脉动压强相对于边界层内的大尺度结构变形率的相位滞后沿壁面法向的变化趋势,分析结果表明剪切湍流涡粘模式中的涡粘系数应该是随时均流梯度变化的复数形式.

The phase delay of the Reynolds stress and the wall pressure fluctuations at the scales of coherent structures corresponding to the strain rate of the large scale structures in turbulent boundary layers have been studied. Introducing the periodic disturbance of wake vortex by a circular cylinder in the outer layer of the turbulent boundary layer on a flat plate, the measurements in the wake flow and the logarithm law region downstream the cylinder confirm that the local Reynolds stress and the wall pressure fluctuations have a mean phase delay corresponding to the phase of the strain rate of the large scale structures in turbulent boundary layers. The tendency of the mean phase delay varying as the distance from the wall suggests that the eddy viscosity modeling of the wall shear flow should have a complex form and changed as the shear strength varied.